What Effects Can Surface Acid Pickling Treatment of UHPC Panels Achieve and Its Mechanism Analysis

Surface treatment is the soul of UHPC panel performance and aesthetics; the acid-washing process brings out both engineering value and artistic vitality in every panel.

As a technology leader in the field of new architectural decoration materials, Qinglong Group has specialized in UHPC/GRC/GRG/GRP materials for 28 years. With the mission of "creating beautiful architecture," it has continuously explored core technologies for optimizing material performance across the entire chain from detailed design and manufacturing to construction and installation. Among these, surface acid-washing of UHPC panels, as a key process for enhancing the comprehensive value of materials, is becoming a technical focus in the high-end architectural decoration field.

1. Core Effects of UHPC Panel Acid-Washing: A Dual Breakthrough from Performance to Aesthetics

UHPC (Ultra-High Performance Concrete), with its ultra-high strength, excellent durability and other properties, has been widely used in high-end settings such as grand theaters, commercial complexes, and landmark buildings. Acid-washing achieves three core effects through precise control of acid concentration and reaction time: First, by selectively dissolving the surface cement paste, it exposes the evenly distributed steel fibers and quartz sand inside, forming a micron-scale rough surface that increases the panel's friction coefficient by more than 30%, significantly enhancing the stability of facing tile bonding or coating adhesion; Second, it dissolves free calcium on the surface, reducing the risk of alkali-aggregate reaction. In cyclic tests from -40°C to 80°C, treated UHPC panels endured over 1,000 freeze-thaw cycles, a 40% improvement in durability; Third, it creates a natural stone-like texture. By controlling the pickling depth (typically 0.2-0.5mm), it can simulate the visual effects of natural stones such as sandstone and granite, meeting designers' diverse aesthetic demands for building skins.

2. The Scientific Mechanism of Acid-Washing: Micro-Level Control Driving Macro-Level Performance Gains

Through electron microscope observations, Qinglong's technical team found that the acid-washing process of UHPC panels follows a dual-stage "dissolution-reconstruction" mechanism. In the initial stage (0-30 seconds), a 10%-15% dilute hydrochloric acid solution rapidly dissolves surface calcium hydroxide and ettringite, forming a honeycomb-like pore structure; as the reaction proceeds (30-90 seconds), the acid penetrates to a depth of 200-500μm and reacts with unhydrated cement particles, and the released silica gel forms a dense siloxane-bond protective layer on the pore surfaces. This optimization of the microstructure raises the panel's surface hardness from 35MPa before treatment to 48MPa, while reducing capillary water absorption by 60%. Notably, Qinglong's independently developed "gradient acid-washing process," which controls the acid temperature in stages (5°C → 25°C → 5°C), enables precise control of the layered texture of the surface. This technology has been applied in benchmark projects such as the Nanjing East Road Century Plaza renovation project, winning the AALBORG WHITE Cup UHPC Construction Engineering Innovation Award.

3. Process Value from a Full-Chain Perspective: Closed-Loop Management from Laboratory to Construction Site

As a national-level high-tech enterprise, Qinglong has established a whole-process quality control system covering everything from material formulation design to construction acceptance. In the acid-washing process, automated spraying equipment and real-time pH monitoring systems ensure that the treatment uniformity error per square meter of panel is ≤2%. Compared with traditional manual acid-washing, the automated process triples production efficiency, and the flatness error of acid-washed panels is controlled within 0.5mm/m, laying the foundation for "zero-error" jointing in subsequent installation. In the Dongguan Women and Children's Activity Center project, Qinglong's acid-washed UHPC exterior wall panels not only achieved the "water ripple" visual effect required by the designers, but also withstood the test of force-12 strong winds in a typhoon-prone environment, demonstrating a perfect combination of material performance and engineering practice.

From technical principles to engineering applications, the surface acid-washing of UHPC panels is both a micro-level exploration in materials science and a macro-level expression of architectural aesthetics. Building on 28 years of industry experience, Qinglong Group will continue to drive technological innovation in UHPC/GRC/GRG/GRP materials, providing designers and owners with "one-stop" solutions from detailed design to after-sales maintenance, and helping realize the vision of "becoming a world-class leading enterprise in architectural decoration materials manufacturing." In the field of new building materials, the value of the acid-washing process lies not only in enhancing material performance, but also in making every panel an artistic carrier of architectural aesthetics and engineering safety.